diff --git a/src/warden-server/lib/Warden.pm b/src/warden-server/lib/Warden.pm
index 1e4184a2f2db690f2f7fe62f86d5d6ce6a827a18..3eeccebdfdb93fc947899fb112bd961704f5c239 100755
--- a/src/warden-server/lib/Warden.pm
+++ b/src/warden-server/lib/Warden.pm
@@ -231,11 +231,11 @@ sub saveNewEvent
     }
 
     my $change_string = "";
-    if ($target_port !~ /^\d+\z/) {
+    if (defined $target_port && $target_port !~ /^\d+\z/) {
       $change_string = $change_string . "target_port: '$target_port'";
       $target_port = undef;
     }
-    if ($attack_scale !~ /^\d+\z/) {
+    if (defined $attack_scale && $attack_scale !~ /^\d+\z/) {
       if ($change_string eq "") {
         $change_string = $change_string . "attack_scale: '$attack_scale'";
       } else {
@@ -243,7 +243,7 @@ sub saveNewEvent
       }
       $attack_scale = undef;
     }
-    if ($priority !~ /^\d+\z/) {
+    if (defined $priority && $priority !~ /^\d+\z/) {
       if ($change_string eq "") {
         $change_string = $change_string . "priority: '$priority'";
       } else {
@@ -251,7 +251,7 @@ sub saveNewEvent
       }
       $priority = undef;
     }
-    if ($timeout !~ /^\d+\z/) {
+    if (defined $timeout && $timeout !~ /^\d+\z/) {
       if ($change_string eq "") {
         $change_string = $change_string . "timeout: '$timeout'";
       } else {